Fluxgate compasses give an indication of the direction of an object in which the compass is installed by sensing the horizontal component of the earth's magnetic field. Fluxgate compasses operate by alternately magnetically saturating a permeable core with a drive coil and detecting, using sensing coils, the asymmetry of the resultant magnetic field, the asymmetry having been caused by the earth's magnetic field.
In order to sense direction accurately, it is necessary both for the fluxgate (coils and core) to be retained in directional alignment relative to the object and also for the fluxgate to be retained horizontally, so that the true horizontal component of the earth's magnetic field is sensed.
In Great Britain Pat. No. 2107057, a suspension assembly for a fluxgate is proposed in which the fluxgate is connected to a supporting frame to be mounted relative to the object, by means of a spherically symmetrical mechanical coupling which permits both tilt and twist. Thus, if the object tilts away from horizontal, the fluxgate will remain, due to its weight, in the horizontal plane. A flexible circuit is provided which both keeps the fluxgate directionally aligned and provides electrical connections thereto.
The largest factor in the cost of this prior art teaching is the mechanism used to support the fluxgate. To a large extent, this mechanism is there to support itself, with the essential mechanism of the fluxgate only being 1/50 of the weight of the whole suspended assembly.